Ferrous alloys



TES

=1 NIT 1 iii.

HENRY L. COLES, OF HAMILTON, OHIO, ASSIGNOR TO GUARDIAN METALQCOIVCPANY, 0F HAMILTON, OHIO, A CORPORATION OF DELAWARE FERROUS ALLOYSNo Drawing.

ture and require special precautions in the preparation of the variousalloys thereof and in the fabrication of articles prepared therefrom.

It is an object of the present invention to provide an improved ferrousalloy having a high degree of hardness and torch resistance.

It is also an object of this invention to provide an improved ferrousalloy containing substantial amounts of manganese, chromium and carbon.

Another object of this invention is to provide an improved compositioncomprising major amounts of iron and substantial amounts of combinedmanganese, chromium, and carbon.

These, and other desirable objects and advantages of the presentinvention will be described in the accompanying specification, certainpreferred compositions being disclosed by way of example only, for,since the improvements of the present invention may be comprehended inother specific compositions, it is not intended to be herein limited tothe ones set forth as examples except as such limitations are clearlyimposed by the appended claims.

In one of the desired practical embodiments the improved alloy of thepresent invention preferably comprises substantially 15 to 18 per centmanganese, 7 to 15 per cent chromium, 2.2 to 3 percent carbon, and theremainder iron. While these percentages have been set forth asdeterminative of the preferred range of the compositions included inthis invention, it will, of course, be understood that variations in theamounts of the several components may be made without de- Applicationfiled March 22, 1930. Serial No. 438,232.

parting from the spirit and scope of this invention. As exemplifyingspecific compositions which have been found to give desirable results,the following are noted:

No. 1?!) 3i g 12?:

All of the alloys above described have a scratch hardness ofsubstantially 7.4 to 9 on Mohs scale, and are markedly torch-resistantand drill resistant.

While a'preferred range of compositions has been disclosed, theinvention comprehends alloys included within varying percentages, asfollows:

Manganese 13 to 20 per cent Chromium 3'00 18 per cent Carbon 2 to 4 percent Iron 82 to 61 per cent Ferroinanganese 3 to 2 per centFerrochromium 16 to 12 per cent When using scrap from the castings made'-from the above, the following preparations were found to besatisfactory:

Spiegel pig 46 to 57 per cent Ferromanganese 1 to 2 per centFerrochromium 6 to 11 per cent Alloy scrap 47' to 30 percent Theanalysis for manganese, chromium and carbon in the rawrma-terlals usedis as follows:

Ferromanganese 8.4 per cent manganese 4.65 per cent carbon Ferrochromium80.3 per cent chromium 1.49 per cent carbon Spiegeleisen .20.11 per centmanganese 2.97 per cent carbon It is preferred to employ the rockingin-' direct-arcelectric furnace in the prepara-. tion of these improvedalloys. One desired purpose for using this ty of furnace is tosubstantially eliminate t e burning out of manganese from thecomposition as well as to insure homogeneity of the resulting product. YThe metal, after melting, is preferably allowed to set in the ladlwuntil it becomes substantially quiet; It is then poured into molds whichare preferably pre-heated. This pouring is usuall done rapidly and thecastings are allowe to cool slowly for a desired period to preventcracking. This cooling may even extend for twenty-four hours. One methodof accomplishing the desired cooling is to ram up the molds with anexcess thickness of sand to thereby retard the dissipation of heat fromthe casting. Such regulated cooling acts to equalize the stressesnormally set up in the castlng.

It will 'now be appreciated that there has beendescribed novel ferrousalloy compositions having relatively high manganese and g5 chromiumcontents, together witha high carbon content, and which. arecharacterized by a very marked degree of torch and drill re sistance.

It will be particularly noted from the fore- 80 going description thatthe improved allo -described herein accomplishes in a muc more eflicientmanner the heat resistance and drill resistance desired. Further, theseadvantages are obtained by an alloy which is 85 very much reduced incost of manufacture, and gives many advantages not obtained in some ofthe other alloys. This improved alloy is capable of many uses, esecially where it is desired to employ materialwhlch will 40 readilywithstand heat and is especially resistant to the action of drills andother destructive implements.

The im roved alloy herein set forth and described lsdefined as anexample, and it is desired that any modifications or changes thereinshall be considered as being within the scope of this inventionas'outlined' in the following claims.

What is claimed is: I 1. A. hard alloy comprising 14 to about 7 18%manganese, 7 to 9.03% chromium, about 2 to 4% carbon and the balanceiron.

2. A hard alloy comprising about 16.5% manganese, about 9.03% chromium,about 2.19% carbon and the balance iron.

3. A hard alloy com rising about 18% manganese, about 7. 5 0 chromium,about 2.76% carbon, and the balance iron. 4. A hardalloy comprisingabout 16 to- 00 18% manganese, about 8 to less than 9% chromium, andabor 2 to 3.5% carbon and thergalance iit'ion.

y 's speci cation si ed this 21 da of March, 1930. gn y as HENRY L.COLES;

